docs: def wait_until_running(self, callback=None):
          """Waits until the remote worker is running, then calls the callback.
          Usually, this method is passed to a different thread; the callback
          is then a function patching results through to the result queue."""
          status = self.machine.scheduler.wait_until_running(
                  self.job, self.worker_config.time_out)
  
          if status.running:
              self.online = True
              if callback:
                  callback(self)
          else:
              raise TimeoutError("Timeout while waiting for worker to run: " +
                                 self.worker_config.name)